Exodus 23:14-16

14Three times thou shalt keep a feast unto me in the year. 15The feast of unleavened bread shalt thou keep: seven days thou shalt eat unleavened bread, as I commanded thee, at the time appointed in the month Abib (for in it thou camest out from Egypt); and none shall appear before me empty: 16and the feast of harvest, the first-fruits of thy labors, which thou sowest in the field: and the feast of ingathering, at the end of the year, when thou gatherest in thy labors out of the field.